Field of the Invention
This invention relates to a Thin Film Transistor (TFT) used in a Static Random Access Memory (SRAM) or Liquid Crystal Display (LCD) and a method of manufacturing thereof, and more particularly to a TFT having a trench surrounding gate structure that is capable of decreasing the leakage current generated during the Off-State of the TFT by securing a sufficient channel despite the smallness of the area, increasing the driving current by securing enough cross-sectional area of an inverted channel during the On-State of the TFT, and improving the resolution of LCD by reducing the space occupied by the TFT in a panel during the manufacturing of the LCD, and a method of manufacturing the TFT thereof.
Following the conventional method of manufacturing a TFT, a silicon layer used as a TFT channel is flatly formed over an insulating layer, and a TFT gate insulating layer and TFT gate are formed on the silicon layer. Finally, a TFT source and drain are formed by implanting impurities into the silicon layer for a TFT channel.
However, when the conventional method is applied manufacturing a highly integrated SRAM, the area of unit cell is increased so that the chip size is increased. Moreover, the area occupied by the TFT must be minimized during the manufacturing process of the LCD. Therefore, in such case, when applying the typical TFT structure, the resolution of LDC deteriorates.